bredehoft



Jan. 31. 1956 H. A. BREDEHOFT SOUND OUTPUT CONTROL FOR TELEPHONE RINGERS Filed Oct. 16, 1952 l m F Hm I m E 6 Q Q FIG. 2

Un ed St-ates P ten r z'fi ssgss f I 1 SOUND OUTPUT CONTROL "Fort TELEPHONE N E i f .71 Harold AwBredehoft, Millington N. J., assignorto Ben Telephone. Laboratories, Incorporated, .New York, -r a m' a n QiNt Yv Y Application oust r 16,1952, seriarNasitass 1 class. (Cris ina-.397)

This invention relates ,to audible signaling devices of the. percussion typeandparticularly to sound regulators fortel'ephone ringerstg.

The telephone ringer employed attelephone subscrib ers stations comprises an .electromagnetically controlled, vibratile clapperrod whichusupports a,.clapper between two spacedigong's 'insuch. avmanner that, as the rod is vibratedthe clapper strikes the' gongs alternately to produceanaudible signal. In practice, each gong is struck by the clapper on, the overthrow of the clapper rod. That 'is', afterLthe rodpreaches. its maximum swing, in either directionas determined by the amplitude of the stroke of the ringer, armature ,to which the rod is staked or otherwise fixed, the resiliencyrof therod and the inertia ofthe clapper-causethe clapper-supporting end. of the rod to'continue-in the direction ;of the gong, after the commumeatesjivithi thepclapper-supporting rod and parts thereto,thevibrationsof the armature; the position of .the .stop relativegto therarmature-supported. rod; de termines thefimplitude 10f thestrolce of the armature;

The invention will be readily understood-from the fol:-.

lowing detailed ip o fi d with referenceto n yi sdrawtngs, in which:

Fig.1 1 is ,.a,plan view of. aringer involving the features oftheinventiontiq t I 1 Fig. 2 is a'sectional view of the ringer taken along the line :z z ofwFig, l,.looking@in .the direction of the ar r snd. w, i r Fig. 3 is a fragmentary-perspective view of the essential elements of the-sound regulator of the invention.

In, the several figuresof the; drawings thesound regula tort-of the invention-,is illustrated embodied in a ringer structureofthe typedisclosed in W. E. Whidden Patent 2,532,133; of NovemberZS, 1 950. r p r The ,ringer disclosed, in the drawings comprises. an ir. regularly configuredyframe which may. be die-cast of The f ame is a'n integral. formation consisting of a,central.post 12, two substantiallyparallel,arms 15 and 16 projecting at right; angles from, the upper and lower ends, respectively, f I 'PQ U rpair Qf i a y formed gong pest J 13 and 14,0n eachgof which is 'removably mounted, in

movement of the armature hastbeen arrested or its:.di-

attained by the provision of,subscriber-controlledmeans r for adjusting the spacing of the ringer gongs and simultaneously regulating the amplitudeofthe stroke of the clapper rod. -:-;Regula tingthe amplitude of the clapper rod stroke in accordanc'withthe spacing between the ringer-gongsinsures the "striking offflthe gongsby; the

clapper during the overthrow of the clapper rod and precludesthe possibility-- of the" clapper acting to damp the sound vibrations even at clapper rod strokes of small amplitudes.

It is the object of this invention to provide a sound regulator for telephone ringers which is subscriber-controlled; Which insures a high quality of tone regardless of the sound level at which the ringer is adjusted to operate; and which requires no change in the relative positions of the ringer gongs.

This object is attained in accordance with a feature of the invention by locating an eccentrically-shaped clapper between a pair of spaced gongs, and employing subscriber-controlled means for rotating the clapper to vary the clearance between the clapper and one of the ringer gongs and for simultaneously regulating the stroke of the armature in accordance with the clapper-gong spacing. More particularly, the clapper is so designed as an eccentric, and so mounted on the free end of a flexible rod that as the rod is rotated through the medium of a manually operable thumb wheel, the spacing between one gong and the clapper edge is varied between minimum and maximum limits and the spacing between the other gong and the clapper edge remains constant. The manually operable means also controls the spacing between an adjustable stop and an armature-supported rod which any suitable manner, a gong such. as gongs 17 and 18. -=.A.unit,type pole-piecelt) is fixed to the frame arms .15 and 16 :by rneans ofrivets fi This element which is substantially ,identical in construction tothe unit type pole-piecedisclosed in Fig.4 of the. drawings of ,I-L A. Bredehoftet alflPatent 2,590,500 of March 25, 1952, terminates inzextrernities 21 and-22which are so relatively disposed as.t o-define,an;air -gap in which an armature};

is adapted to vibrate under thejointcontrol of a magnet coil 24 and afsmall; cylindrical permanent magnetZS. The armature 23 is mounted on the lower end offthe pole-piece -section 22,by means of a spring-hinge26 while thecoil-24 is-mounted on a laminated; core structure whieh, togetherwith a silicon ,st eel shunt 27, is secured the r m pieces 15am 16b) screws 28- 1 Theelernents. thus falHd eS C ribed constitute essentially, the anagnetic andnelectrical. elementsof the ringerf,and formno part of theipresent invention. ,They are fully disclosed and, described in; the above-mentioned Patent 59 0 p Referring more;particularlytofigs. 2 and 3 itwill be observed that the clapper 30 is constructed as an eccentric andfis mountedpnthe outer end of a flexible rod 3L the inner end of which is staked, or otherwise secured to a small shaft 32 which passes through a suitable opening in the frame piece 12 so as to extend through to the outside of the frame. The shaft portion which projects outside the frame piece 12, that is, to the left, viewing Fig. 2, accommodates a knob or thumb wheel 33 which is fixed to the shaft in any suitable manner such as by a screw 34.

Also mounted on and in fixed relation to the shaft 32 is an L-shaped rod 35 which is herein characterized as an armature stop. The portion of the stop 35 which is associated with the shaft 32 is annular in form and fits securely to the shaft so as to move therewith. A bushing or washer 36 is interposed between the annular portion of stop 35 and the inner face of frame section 12.

The longer portion of the stop rod 35 extends inwardly from the annular portion so as to be in the line of travel of a relatively stiff rod 37 which is staked to the upper or free end of armature 23, and is ring-shaped at its other end. The rod 31 which supports the clapper 30 passes through the opening in the ring-shaped portion of the rod 37 so as to be coupled to and actuated by the rod 37 whenever the armature 23 vibrates.

The thumb wheel 33 is provided with a knurled edge to facilitate finger control of .the sound regulating mechanism and its shank portion is indented at regular, closely spaced intervals to provide means for accommodating the stop lug 33. By means of the stop 38, which is fixed to the frame 12 in any suitable manner, and the depressions on the shank of knob 33 the knob may be set in any of a number of different positions and is locked therein against accidental displacement.

The flexible clapper-supporting rod 31 may be in the nature of a wire which is provided with a series of coils 31:: near its staked end. The rod 31 is designed so as to have'a relatively low stiffness characteristic.

The clapper 30 is so designed and initially positioned relative to gongs 17 and 18 that the clearance to gong 18 is maintained constant While the clearance to gong 17 varies as the thumb wheel 33 is rotated.

In the drawings, the sound regulator is so positioned that the sound signal emitted by the ringer will be at its lowest intensity. In this position the node, or high point 01": the clapper 30 is in its closest relation to gong 17 and the stop rod 35 is in its closest relation to the armature extension 37 so that, when the ringer coil 24 is energized, the armature 23 will vibrate in abbreviated strokes because of the close proximity of the stop 35 to the rod 37. These'armature vibrations are communicated to the clapper rod 31 by the armature extension 37.

' In order to increase the level of the sound signal emitted by the ringer the telephone subscriber rotates the thumb wheel 33 counterclockwise; the stop 35 experiences a similar movement resulting in a greater dis-.

placement of the stop from the armature extension 37, so that when the coil 24 is energized underthis condition the armature 23 will vibrate in strokes of greater length. Simultaneously, the high point of the clapper 30, due to the rotation of the flexible rod 31 by the thumb wheel 33, will have taken up a new position with respect to the surface of gong 17 in which the clearance between gong 17 and the striking area of the clapperis increased. Thus, by the manipulation of the thumb wheel 33, the clapper-to-gong clearance and the armature stroke are simultaneously adjusted in such a manner that any increase in one is accompanied by a corresponding increase in the other and conversely, any decrease in the one is accompanied by a corresponding decrease in the other.

By virtue of the regulating mechanism of this invention an undamped tone signal of uniform high quality is insured irrespective of the sound level at which the signal is produced. Also, the invention is embodied in a sound reg ulator for telephone ringers which readily adapts itself to manual control by the telephone subscriber.

What is claimed is: 1. The combination in a telephone ringer, of a pair of spaced gongs, a resilient clapper rod, an eccentricallyshaped clapper mounted on said rod and adapted to engage said gongs when said rod is vibrated, and means for rotating said clapper and simultaneously regulating the amplitude of vibration of said clapper rod.

2. A sound signal comprising a gong, a vibratile hammer for striking said gong and-including an eccentricallyshaped striker, a stop for said hammer, and means for moving said stop relative'to said hammer and for simultaneously rotating said hammer.

3. A sound signal comprising a gong, an eccentricallyshaped clapper, a rod supporting said clapper and movable in the direction of said gong, means controlling the movement of said rod, 9. stop controlling the movement of said means, and manually-controlled means for rotating said clapper-supporting rod and for simultaneously adjusting the position of said stop.

4. In a telephone ringer, a gong, an electromagnetically controlled vibratile armature, a flexible rod, an eccentrically-shaped clapper carried by said flexible rod in juxtaposition to said gong, means associated with said flexible rod for rotating said clapper to vary the clearance between said gong and said clapper, and means including a rod staked to said armature for communicating the vibrations of said armature to said flexible rod.

5. A telephone ringer in accordance with claim 4 including means controlled by said clapper-rotating means for adjusting the stroke of said armature.

6. In a telephone ringer, a gong, a striker for said gong including an eccentrically-shaped clapper operatively disposed relative to said gong, means for adjusting the stroke of said striker, means for rotating said clapper to alter the clearance between said gong and said clapper, and a single means for eifecting the simultaneous operation of said adjusting means and said rotating means.

7. In a telephone ringer, a pair of gongs, a vibratable clapper rod, a'clapper fixed on said rod for operation between said gongs and adapted to engage said gongs when said rod is vibrated, said clapper having a uniform gong striking periphery and comprising an eccentrically shaped mass whereby when said clapper is rotated relative to said gongs the spacing between one of said gongs and the area of the clapper periphery opposed thereto is varied, and means for rotating said clapper relative to said gongs comprisingrneans for rotating said rod.

References Cited in the file of this patent UNITED STATES PATENTS 1,233,989 Deagan July 17, 1917 1,342,543 Kline June 8, 1920 2,468,474 Whidden Apr. 26, 1949 

